diff --git a/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php b/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php
index c5360ca6..5819eccf 100644
--- a/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php
+++ b/src/Analyser/Parallel/ParallelAnalysisNodeExtractor.php
@@ -553,10 +553,22 @@ private function workerFailure(string $error, string $stderrFile): RuntimeExcept
      */
     private function createWorkerFiles(string $dir): array
     {
+        $created = [];
+
+        try {
+            $created[]  = $inputFile = $this->temporaryFile($dir);
+            $created[]  = $outputFile = $this->temporaryFile($dir);
+            $stderrFile = $this->temporaryFile($dir);
+        } catch (RuntimeException $runtimeException) {
+            $this->cleanup($created);
+
+            throw $runtimeException;
+        }
+
         return [
-            'inputFile'  => $this->temporaryFile($dir),
-            'outputFile' => $this->temporaryFile($dir),
-            'stderrFile' => $this->temporaryFile($dir),
+            'inputFile'  => $inputFile,
+            'outputFile' => $outputFile,
+            'stderrFile' => $stderrFile,
         ];
     }
 
diff --git a/tests/Analyser/Parallel/MockFunctions.php b/tests/Analyser/Parallel/MockFunctions.php
index fb11ef00..c5ac6195 100644
--- a/tests/Analyser/Parallel/MockFunctions.php
+++ b/tests/Analyser/Parallel/MockFunctions.php
@@ -76,6 +76,11 @@ function tempnam(string $directory, string $prefix): string|false
         return false;
     }
 
+    // an int allows that many successful calls before failing
+    if (is_int($GLOBALS['mock_tempnam']) && $GLOBALS['mock_tempnam']-- <= 0) {
+        return false;
+    }
+
     $result = \tempnam($directory, $prefix);
 
     if ($result !== false) {
diff --git a/tests/Analyser/Parallel/ParallelAnalysisNodeExtractorTest.php b/tests/Analyser/Parallel/ParallelAnalysisNodeExtractorTest.php
index cd207221..2217e4ec 100644
--- a/tests/Analyser/Parallel/ParallelAnalysisNodeExtractorTest.php
+++ b/tests/Analyser/Parallel/ParallelAnalysisNodeExtractorTest.php
@@ -736,6 +736,38 @@ public function testExtractThrowsWhenTempnamFails(): void
         }
     }
 
+    public function testExtractRemovesCreatedWorkerFilesWhenLaterTempnamFails(): void
+    {
+        $GLOBALS['mock_missing_functions']     = ['pcntl_fork'];
+        $GLOBALS['mock_tempnam']               = 1;
+        $GLOBALS['mock_tracked_tempnam_files'] = [];
+
+        $dir  = $this->makeTemporaryDirectory('structarmed-parallel-test');
+        $file = $dir . '/Foo.php';
+        file_put_contents($file, '<?php class Foo {}');
+
+        $parallelAnalysisNodeExtractor = new ParallelAnalysisNodeExtractor($dir, [], [], 2);
+
+        try {
+            $parallelAnalysisNodeExtractor->extract([$file]);
+            $this->fail('Expected RuntimeException was not thrown.');
+        } catch (RuntimeException $runtimeException) {
+            $this->assertSame(
+                'Unable to create temporary file for parallel analysis.',
+                $runtimeException->getMessage()
+            );
+
+            /** @var list<string> $created */
+            $created = $GLOBALS['mock_tracked_tempnam_files'];
+            $this->assertCount(1, $created);
+            $this->assertFileDoesNotExist($created[0]);
+        } finally {
+            $GLOBALS['mock_missing_functions']     = [];
+            $GLOBALS['mock_tempnam']               = false;
+            $GLOBALS['mock_tracked_tempnam_files'] = [];
+        }
+    }
+
     public function testExtractThrowsWhenPayloadIsInvalid(): void
     {
         $GLOBALS['mock_file_get_contents_payload'] = ['invalid' => 'payload'];